1. Field of the Invention
The present invention relates to a fuel injection device that performs injection supply of fuel to an internal combustion engine. In particular, the present invention relates to a fuel injection device that controls seating and separation of a valve member to and from a valve seat with pressurized fuel.
2. Description of Related Art
Conventionally, there is a known fuel injection device that pressurizes a fluid by driving a driver to separate a valve member from a valve seat, thereby injecting fuel (for example, refer to Patent document 1: US 2003/0116656 A1). There is also a publicly known fuel injection device structured such that a valve member lifts in a direction, in which the valve member separates from a valve seat, when fuel pressure of a fuel pressure control system is increased by a piston, thereby injecting the fuel from an injection hole communicating with a fuel passage.
In such the fuel injection device, fuel leak arises from a sliding section between the piston and a cylinder member since the fuel pressure control system is pressurized. In order to prevent the fuel leak, it is necessary to secure axial length of the sliding section. However, if the axial length of the sliding section is secured, the body size of the piston increases and the movable mass increases. Accordingly, an inertial resistance caused in the piston increases, leading to an energy loss.